There is a reason no video can be found on this. - IMG AR-10 .308 12 Gauge 19in Complete Upper Receiver w/Two 5 Round Magazine

Junk! The bolt doesn't go back far enough to feed or eject. I dropped a round in the barrel and it fires. Then take out the magazine put it on safe and dig out the spent round with a knife. The bolt hold open engagement works. So its either bad design or bad magazine that it comes with. I'm going to buy some different magazines and see if that works. Don't waste your money and time on this!